ROAD CONSTRUCTION: Calif. completes Devil’s Slide tunnels

The new tunnels bypass a curvy section of S.R. 1 that has been plagued by rockslides

News Caltrans March 27, 2013
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Caltrans cut the ribbon Monday March 25 for the first new highway tunnels in California in nearly 50 years and the longest tunnels in the state—the new Devil’s Slide Tunnels on State Rte. 1 in San Mateo County. The tunnels will officially open to the public Tuesday March 26.


“Today, we mark the start of a new chapter for both Caltrans and the local communities,” said Caltrans Director Malcolm Dougherty. “No longer will local residents and businesses have to worry about severe winter storms closing the road and disrupting their lives.”


The $439 million project features two 4,200-ft-long tunnels, 32 jet-powered fans for ventilation and 10 fireproof shelters between the tunnels to protect the public.


The new tunnels, located about 15 miles south of San Francisco between Pacifica and Half Moon Bay, bypass a curvy section of S.R. 1 built in 1937 that has been plagued by rockslides and repeatedly erodes and collapses.


Caltrans has closed the road many times for extended periods to make emergency repairs, hampering local residents and businesses. Each closure turns a 7-mile drive from Pacifica to Montara into a 45-mile detour. One of the longest closures happened in 1995. It lasted 158 days.


“Devil’s Slide has been an enormous undertaking in difficult terrain,” said Brian Kelly, acting secretary of the Business, Transportation and Housing Agency. “Ingenuity, will, and perseverance combined to get this project done. The new tunnels are state-of-the-art structures that blend well into the beautiful, natural surroundings on this stretch of Highway 1. Thanks to the work of the men and women who dedicated themselves to completing this project, motorists and emergency responders will have a safer journey from this day forward.”


For more information about the tunnels, please visit:

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